Ductilization of a diffusion-bonded heterostructured AZ31/GW103K/AZ31 alloy by interfacial reinforcement

Heterostructured materials are an emerging class of materials with superior performances that are unattainable by their conventional homogeneous counterparts, and have recently attracted extensive attentions from the materials community. However, due to the hcp crystal structure, the conventional processing methods of heterostructured materials are difficult to be applied in Mg alloys. To overcome the negative effects, namely poor formability and easy oxidation, in Mg alloys, diffusion bonding under an ultra-vacuum condition was employed to prepare multi-layer heterostructured materials with different alloys, i.e. AZ31 (Mg–3Al–1Zn wt. %) and GW103 K (Mg-10Gd-3Y-0.4Zr wt. %) alloys. Moreover, the reinforcement of interface was further improved by interaction of alloying elements during post-annealing. The new formed interfacial phase was found to be the main reason for the reinforcement of interface. Without a decrease of strength, the ductility of post-annealed samples was increased to more than twice of the diffusion bonded ones. Based on high resolution TEM observation, the crystal lattice of the interfacial phase was determined as a fcc structure with a lattice parameter of a = 7.9 Å.